You can find many adjustable rear sight "take offs" from MK series on eBay. While looking for an optic adapter for my Ruger P series, I noted that the adapter was for Ruger MK series and P series. If I tire of the optic on the P93 I considered installing the adjustable rear sight from my MKIII that I took off for an Optic.
when you put the Ruger ( factory) rear adjustable sight in the dovetail of any of the "fixed" sight guns mark I or II or whatever, you will need to put a HIGHER front sight blade on the gun.......there are LPA ( Low profile adjustable ) sights from Midway , or brownells that use the current , lower front sight blade thats already on the gun..........................
